Mammalia Linnaeus 1758 [Rowe 2020] Theria Parker & Haswell 1897 [McKenna 1975] see Subclass Theria Parker & Haswell, 1897 Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880 †Deltatheroida Kielan-Jaworowska 1982 see Order Deltatheroida Kielan-Jaworowska, 1982 Genus †Deltatheroides Gregory & Simpson, 1926